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authorJan Kara <jack@suse.cz>2015-05-21 16:05:56 +0200
committerAl Viro <viro@zeniv.linux.org.uk>2015-06-23 18:01:10 -0400
commita6de82cab123beaf9406024943caa0242f0618b0 (patch)
tree747d73350fb02ca51306530630766dd28b8d0548 /fs
parent45f147a1bc97c743c6101a8d2741c69a51f583e4 (diff)
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xfs: Correctly lock inode when removing suid and file capabilities
Currently XFS calls file_remove_privs() without holding i_mutex. This is wrong because that function can end up messing with file permissions and file capabilities stored in xattrs for which we need i_mutex held. Fix the problem by grabbing iolock exclusively when we will need to change anything in permissions / xattrs. Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs')
-rw-r--r--fs/xfs/xfs_file.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index f3e4fbb59985..71c2c712e609 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -563,6 +563,13 @@ restart:
if (error)
return error;
+ /* For changing security info in file_remove_privs() we need i_mutex */
+ if (*iolock == XFS_IOLOCK_SHARED && !IS_NOSEC(inode)) {
+ xfs_rw_iunlock(ip, *iolock);
+ *iolock = XFS_IOLOCK_EXCL;
+ xfs_rw_ilock(ip, *iolock);
+ goto restart;
+ }
/*
* If the offset is beyond the size of the file, we need to zero any
* blocks that fall between the existing EOF and the start of this
@@ -623,7 +630,9 @@ restart:
* setgid bits if the process is not being run by root. This keeps
* people from modifying setuid and setgid binaries.
*/
- return file_remove_privs(file);
+ if (!IS_NOSEC(inode))
+ return file_remove_privs(file);
+ return 0;
}
/*